1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)scandir.3 8.1 (Berkeley) 6/4/93 29.\" $FreeBSD: src/lib/libc/gen/scandir.3,v 1.3.2.5 2003/03/15 15:11:05 trhodes Exp $ 30.\" 31.Dd May 5, 2019 32.Dt SCANDIR 3 33.Os 34.Sh NAME 35.Nm scandir , 36.Nm alphasort 37.Nd scan a directory 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In sys/types.h 42.In dirent.h 43.Ft int 44.Fo scandir 45.Fa "const char *dirname" 46.Fa "struct dirent ***namelist" 47.Fa "int (*select)(const struct dirent *)" 48.Fa "int (*compar)(const struct dirent **, \:const struct dirent **)" 49.Fc 50.Ft int 51.Fn alphasort "const struct dirent **d1" "const struct dirent **d2" 52.Sh DESCRIPTION 53The 54.Fn scandir 55function 56reads the directory 57.Fa dirname 58and builds an array of pointers to directory 59entries using 60.Xr malloc 3 . 61It returns the number of entries in the array. 62A pointer to the array of directory entries is stored in the location 63referenced by 64.Fa namelist . 65.Pp 66The 67.Fa select 68argument is a pointer to a user supplied subroutine which is called by 69.Fn scandir 70to select which entries are to be included in the array. 71The select routine is passed a 72pointer to a directory entry and should return a non-zero 73value if the directory entry is to be included in the array. 74If 75.Fa select 76is null, then all the directory entries will be included. 77.Pp 78The 79.Fa compar 80argument is a pointer to a user supplied subroutine which is passed to 81.Xr qsort 3 82to sort the completed array. 83If this pointer is null, the array is not sorted. 84.Pp 85The 86.Fn alphasort 87function 88is a routine which can be used for the 89.Fa compar 90argument to sort the array alphabetically. 91.Pp 92The memory allocated for the array can be deallocated with 93.Xr free 3 , 94by freeing each pointer in the array and then the array itself. 95.Sh RETURN VALUES 96Returns \-1 if the directory cannot be opened for reading or if 97.Xr malloc 3 98cannot allocate enough memory to hold all the data structures. 99.Sh SEE ALSO 100.Xr directory 3 , 101.Xr malloc 3 , 102.Xr qsort 3 , 103.Xr dir 5 104.Sh HISTORY 105The 106.Fn scandir 107and 108.Fn alphasort 109functions appeared in 110.Bx 4.2 . 111